JP7492142B2 - Light-emitting devices, lamps and lighting equipment - Google Patents

Description

The present invention relates to a light-emitting device, a lamp, and a lighting fixture.

A white light-emitting device that uses a blue-emitting light-emitting element and a yellow-emitting phosphor is known as a light-emitting device that uses a light-emitting element such as a light-emitting diode (LED). Such light-emitting devices are used in a wide range of fields, including general lighting, vehicle lighting, displays, and LCD backlights. As LED lighting becomes more widespread, interest is growing in the effects that LED lighting has on the human body. For example, Patent Document 1 describes that LED lighting can affect human circadian rhythms (biorhythms).

In mammalian retinas, there exist new photoreceptors called intrinsically photosensitive retinal ganglion cells (hereinafter referred to as "ipRGCs") that are separate from rods and cones. ipRGCs contain a visual pigment called melanopsin, and have been shown to be involved in non-visual functions such as photoentrainment of circadian rhythms and pupillary reflex. Control of the intrinsic light response of ipRGCs is extremely important in forming circadian rhythms.

Melanopsin is also involved in the secretion or suppression of melatonin, a sleep-promoting hormone; for example, it is believed that increasing the amount of stimulation to ipRGC suppresses the secretion of melatonin. In order to support the formation of human circadian rhythms, it is appropriate to expose oneself to light that corresponds to the time of one's activity. For example, lighting used in living rooms and bedrooms is preferably one that irradiates a warm, calming atmosphere and that is likely to promote the secretion of melatonin.

International Publication No. 2012/144087

One aspect of the present invention aims to provide a light-emitting device, a lamp, and a lighting fixture that emits light that is likely to promote the secretion of melatonin.

The first aspect is a light-emitting device comprising a light-emitting element having an emission peak wavelength in the range of 400 nm to 490 nm, and a first phosphor having an emission peak wavelength in the range of 570 nm to 680 nm, the light-emitting device emitting light having a correlated color temperature of 1950 K or less, an average color rendering index Ra of 40 or more, a full width at half maximum of an emission spectrum showing the maximum emission intensity in the emission spectrum of the light-emitting device of 110 nm or less, and a melanopic ratio MR derived from the following formula (1) of 0.233 or less.

(In formula (1), S(λ) is the spectral radiance of the light emitted by the light emitting device, V(λ) is the standard relative luminous efficiency curve for human photopic vision defined by the CIE (Commission Internationale de l'Eclairage), and R _m (λ) is the sensitivity curve of mammalian intrinsically photosensitive retinal ganglion cells (ipRGC) defined by the CIE (Commission Internationale de l'Eclairage).)

A second aspect is a light emitting device including a light emitting element having an emission peak wavelength in the range of 400 nm or more and 490 nm or less, and a first phosphor having an emission peak wavelength in the range of 570 nm or more and 680 nm or less, wherein the first phosphor includes a first nitride phosphor having a composition represented by the following formula (1A), and the light emitting device emits light having a correlated color temperature of 1950 K or less, an emission spectrum showing the maximum emission intensity in the emission spectrum of the light emitting device having a full width at half maximum of 110 nm or less, and a melanopic ratio MR derived from formula (1) of 0.233 or less.
^M12Si5N8 _{: Eu} ( _1A )
(In formula ( 1A ), ^M1 is an alkaline earth metal element including at least one selected from the group consisting of Ca, Sr, and Ba.)

The third aspect is a lamp equipped with the light-emitting device.

The fourth aspect is a lighting fixture equipped with the light-emitting device.

According to one aspect of the present invention, it is possible to provide a light-emitting device, a lamp, and a lighting fixture that emits light that is likely to promote the secretion of melatonin.

FIG. 1 is a diagram showing the sensitivity curve R _m (λ) of the ipRGC and the standard luminous efficiency curve V(λ) of human photopic vision. FIG. 2 shows the CIE 1931 chromaticity diagram, the spectrum locus on the CIE 1931 chromaticity diagram, the blackbody radiation locus within the pure violet locus, and color deviations from the blackbody radiation locus. FIG. 3 is an enlarged view of a portion of FIG. 2, showing the blackbody radiation locus within a range in which the x value of the chromaticity coordinates in the CIE 1931 chromaticity diagram is 0.300 or more and 0.600 or less and the y value is 0.250 or more and 0.500 or less, and showing each locus of color deviation from the blackbody radiation locus at each correlated color temperature. FIG. 4 is a schematic cross-sectional view showing an example of a light emitting device according to the first configuration example. FIG. 5 is a schematic cross-sectional view showing an example of a light emitting device according to the first configuration example. FIG. 6 is a schematic perspective view showing an example of a light emitting device according to the second configuration example. FIG. 7 is a schematic cross-sectional view showing an example of a light emitting device according to the second configuration example. FIG. 8 is a schematic cross-sectional view showing another example of the light emitting device according to the second configuration example. FIG. 9 is a diagram showing an example of a street light. FIG. 10 is a diagram showing an example of installation of a low-position lighting device, which is an example of a street light. FIG. 11 is a diagram showing the reflection spectra of dielectric multilayer film-1 (DBR-1), dielectric multilayer film-2 (DBR-2), and dielectric multilayer film-3 (DBR-3) at an incident angle of 0 degrees. FIG. 12 is a schematic cross-sectional view showing an example in which a band-pass filter layer is disposed in the light-emitting device of the first configuration example. FIG. 13 is a diagram showing the spectral radiance of the light emitting device of Example 1 and the light emitting device of Comparative Example 3, the sensitivity curve R _m (λ) of ipRGC, and the standard relative luminous efficiency curve V(λ) of human photopic vision. FIG. 14 is a diagram showing the spectral radiance of the light emitting device of Example 2 and the light emitting device of Comparative Example 3, the sensitivity curve R _m (λ) of ipRGC, and the standard relative luminous efficiency curve V(λ) of human photopic vision. FIG. 15 is a diagram showing the spectral radiance of the light emitting device of Example 3 and the light emitting device of Comparative Example 3, the sensitivity curve R _m (λ) of ipRGC, and the standard relative luminous efficiency curve V(λ) of human photopic vision. FIG. 16 is a diagram showing the spectral radiance of the light emitting device of Example 4 and the light emitting device of Comparative Example 3, the sensitivity curve R _m (λ) of ipRGC, and the standard relative luminous efficiency curve V(λ) of human photopic vision. FIG. 17 is a diagram showing the spectral radiance of the light emitting device of Comparative Example 1 and the light emitting device of Comparative Example 3, the sensitivity curve R _m (λ) of ipRGC, and the standard relative luminous efficiency curve V(λ) of human photopic vision. FIG. 18 is a diagram showing the spectral radiance of the light emitting device of Comparative Example 2 and the light emitting device of Comparative Example 3, the sensitivity curve R _m (λ) of ipRGC, and the standard relative luminous efficiency curve V(λ) of human photopic vision. Figure 19 shows the emission spectrum of the light emitting device of Example 1, the emission spectrum after transmission through the bandpass filter layer of the light emitting device of Example 5, and the emission spectrum after transmission through the bandpass filter layer of the light emitting device of Example 6. Figure 20 shows the emission spectrum of the light emitting device of Example 2, the emission spectrum after transmission through the bandpass filter layer of the light emitting device of Example 7, and the emission spectrum after transmission through the bandpass filter layer of the light emitting device of Example 8. Figure 21 shows the emission spectrum of the light emitting device of Example 3, the emission spectrum after transmission through the bandpass filter layer of the light emitting device of Example 9, and the emission spectrum after transmission through the bandpass filter layer of the light emitting device of Example 10. Figure 22 shows the emission spectrum of the light emitting device of Example 4, the emission spectrum after transmission through the bandpass filter layer of the light emitting device of Example 11, and the emission spectrum after transmission through the bandpass filter layer of the light emitting device of Example 12.

Hereinafter, a light-emitting device, a lamp, and a lighting fixture according to an embodiment of the present invention will be described. However, the embodiment shown below is an example of a light-emitting device, a lamp, and a street lamp for realizing the technical concept of the present invention, and the present invention is not limited to the light-emitting device and the lamp and street lamp equipped therewith.
The relationship between color names and chromaticity coordinates, the relationship between light wavelength ranges and color names of monochromatic light, etc., are in accordance with JIS Z8110. Furthermore, when a composition contains multiple substances corresponding to each component, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified.

The light emitting device of the first embodiment is a light emitting device including a light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm, and a first phosphor having an emission peak wavelength in the range of 570 nm to 680 nm, and the light emitting device emits light having a correlated color temperature of 1950 K or less, an average color rendering index Ra of 40 or more, a full width at half maximum of an emission spectrum showing the maximum emission intensity in the emission spectrum of the light emitting device of 110 nm or less, and a melanopic ratio MR derived from the following formula (1) of 0.233 or less.

In the above formula (1), S(λ) is the spectral radiance of the light emitted by the light-emitting device, V(λ) is the standard relative luminous efficiency curve for human photopic vision defined by the CIE (Commission Internationale de l'Eclairage), and R _m (λ) is the sensitivity curve of mammalian intrinsically photosensitive retinal ganglion cells (ipRGCs) defined by the CIE (Commission Internationale de l'Eclairage).

The light emitting device of the second embodiment is a light emitting device including a light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm and a first phosphor having an emission peak wavelength in the range of 570 nm to 680 nm, the first phosphor including a first nitride phosphor having a composition represented by formula (1A) described below, the light emitting device emits light having a correlated color temperature of 1950 K or less, an emission spectrum having an emission peak wavelength that is the maximum emission intensity in the emission spectrum of the light emitting device with a full width at half maximum of 110 nm or less, and a melanopic ratio MR derived from formula (1) of 0.233 or less.

The idea of Human Centric Lighting (HCL) is becoming more widespread. For example, WELL certification, a new building certification that focuses on the health of workers, lists circadian rhythm-friendly lighting as a required item of the certification. Equivalent melanopic illuminance is used as a quantitative unit of brightness that affects circadian rhythm. To calculate equivalent melanopic illuminance, the melanopic ratio MR (Melanopic Ratio) is required, which is calculated from the spectral distribution of the light source. The melanopic ratio MR can be calculated from the above formula (1), and the equivalent melanopic illuminance can be calculated from the following formula (2).

ipRGCs contain a visual pigment called melanopsin, and have been shown to be involved in non-visual functions such as light entrainment of circadian rhythms and pupillary reflexes. ipRGCs are cells that send light signals when directly administered to the suprachiasmatic nucleus. The suprachiasmatic nucleus is a very small area in the hypothalamus of the brain that acts as an internal clock that controls the circadian rhythms of mammals, and its approximately 20,000 neurons create circadian rhythms for various physiological functions such as sleep, wakefulness, blood pressure, body temperature, and hormone secretion.

Melanopsin, which ipRGC possesses, is a photoreceptor protein that is expressed in approximately 1% to 2% of retinal ganglion cells. The majority of other retinal ganglion cells are not photosensitive. It is known that the absorption characteristics of the photoreceptor material differ depending on the cell, and in the case of melanopsin, the maximum sensitivity (peak sensitivity wavelength) is around 480 nm to 490 nm. Figure 1 shows the sensitivity curve R _m (λ) of ipRGC defined by the CIE and the standard relative luminous efficiency curve V (λ) of human photopic vision defined by the CIE. The maximum sensitivity (peak sensitivity wavelength) of the standard relative luminous efficiency curve of human photopic vision is 555 nm.

To calculate the melanopic ratio MR, the sensitivity curve R _m (λ) of the melanopsin response of ipRGC is used as the circadian action curve. When the light emitting device emits light with a melanopic ratio MR of 0.233 or less derived from the above formula (1), it is possible to irradiate light that stimulates ipRGC less, promotes melatonin secretion, and naturally induces sleep. For example, the light emitting device can be used as a light source for indoor lighting used in private spaces such as living rooms and bedrooms where a calm atmosphere is required, or as a light source for vehicle lighting. In order to suppress stimulation of the ipRGCs, the light-emitting device may emit light having a melanopic ratio MR of 0.233 or less, may emit light having a melanopic ratio MR of 0.232 or less, may emit light having a melanopic ratio MR of 0.231 or less, may emit light having a melanopic ratio MR of 0.002 or more, may emit light having a melanopic ratio MR of 0.010 or more, may emit light having a melanopic ratio MR of 0.020 or more, or may emit light having a melanopic ratio of 0.100 or more.

Color temperature is an objective measure of the color emitted by a white light source. When a black body is heated from the outside and the temperature is increased, the color changes from black to dark red, red, yellow, orange, white, and bluish-white. The temperature of a black body is expressed in Kelvin (K), and the correlated color temperature (Tcp; K) and color deviation duv from the black body radiation locus can be measured in accordance with JIS Z8725, and the average color rendering index Ra can be measured in accordance with JIS Z8726. Generally, a bonfire has a color temperature of about 800 K, a candle flame has a color temperature of about 1900 K, incandescent light bulb lighting has a color temperature of about 2900 K, and fluorescent light bulb lighting has a color temperature of about 4200 K.

The light emitting device emits light with a correlated color temperature of 1950K or less, and emits light that is warm and gives a sense of a calming atmosphere. The correlated color temperature of the light emitted from the light emitting device may be 1920K or less, or may be 1900K or less. The correlated color temperature of the light emitted from the light emitting device is preferably 800K or more, preferably 1000K or more, may be 1200K or more, 1500K or more, or may be 1700K or more.

Color rendering indicates the degree of visibility of an illuminated object at the same correlated color temperature. The average color rendering index Ra, which is the average value of R1 to R8 for the light emitted by a light emitting device, can be measured in accordance with the JIS Z8726 method for evaluating the color rendering of light sources. The average color rendering index Ra of the light emitted by the light emitting device may be 5 or more, 10 or more, 20 or more, 30 or more, 40 or more, preferably 51 or more, and more preferably 52 or more. The closer the average color rendering index Ra of the light emitted by the light emitting device is to 100, the closer the color rendering is to the reference light source at the same correlated color temperature. Lighting fixtures installed outdoors or indoors near the outdoors, such as street lights and road lighting, only need to emit light with an average color rendering index Ra of 5 or more. If the average color rendering index Ra of the light emitted by the light emitting device is 40 or more, it has the necessary level of color rendering in a place where work such as sorting luggage is performed, and has sufficient color rendering when performing light work in private spaces such as living rooms and bedrooms. The general color rendering index Ra of the light emitted by the light emitting device may be 53 or more, 99 or less, 95 or less, or 89 or less.

The special color rendering index R9 of the light emitted by the light emitting device is an index for evaluating the color red. The special color rendering index R9 of the light emitted by the light emitting device may be a negative numerical value. The special color rendering index R9 of the light emitted by the light emitting device may be in the range of minus (-) 150 or more and plus (+) 99 or less, in the range of -140 or more and +98 or less, or in the range of -135 or more and 95 or less.

In the light emitting device, the full width at half maximum of the emission spectrum showing the maximum emission intensity in the emission spectrum of the light emitting device is 110 nm or less, may be 100 nm or less, 95 nm or less, 90 nm or less, 3 nm or more, 40 nm or more, 60 nm or more, or 70 nm or more. In the emission spectrum of the light emitting device, if the full width at half maximum of the emission spectrum showing the maximum emission intensity is large, the components of light on the long wavelength side that are difficult for humans to detect will be large, or the components of light on the short wavelength side that are easy to stimulate ipRGC will be large. If the components of light on the long wavelength side are increased, the luminance of the light emitted from the light emitting device tends to decrease. If the components of light on the short wavelength side are increased, the secretion of melatonin tends to be inhibited. In addition, in the emission spectrum of the light emitting device, if the full width at half maximum of the emission spectrum showing the maximum emission intensity is small, the components of light in a specific wavelength range tend to increase. In the emission spectrum of the light emitting device, if the emission peak wavelength having the maximum emission intensity is on the long wavelength side and the components of light on the long wavelength side that are difficult for humans to detect are increased, it becomes difficult to suppress the decrease in luminance. In addition, in the emission spectrum of the light-emitting device, the emission peak with the maximum emission intensity is on the short wavelength side, and when the component of light on the short wavelength side that is likely to stimulate ipRGC becomes large, the secretion of melatonin is easily inhibited. In order to provide a light-emitting device that emits light that is likely to promote the secretion of melatonin without reducing the brightness, it is preferable that the full width at half maximum of the emission spectrum showing the maximum emission intensity in the emission spectrum is 110 nm or less. In this specification, the full width at half maximum refers to the wavelength width in the emission spectrum where the emission intensity is 50% of the emission intensity at the emission peak wavelength showing the maximum emission intensity.

In the emission spectrum of the light emitting device, the full width at half maximum of the emission spectrum showing the maximum emission intensity may be narrower than the full width at half maximum of the emission spectrum having the emission peak wavelength of the first phosphor contained in the light emitting device or the full width at half maximum of the emission spectrum having the emission peak wavelength of the second phosphor described below. For example, when a first phosphor and a second phosphor having emission peak wavelengths in different wavelength ranges are included, the emission intensity of the portion where the emission spectrum of the first phosphor and the emission spectrum of the second phosphor overlap changes, and as a result, the emission spectrum of the mixed color light emitted from the light emitting device may be different from the emission spectrum of the first phosphor or the emission spectrum of the second phosphor, and may be narrower than the full width at half maximum of the emission spectrum having the emission peak wavelength of the first phosphor or the full width at half maximum of the emission spectrum having the emission peak wavelength of the second phosphor.

In the emission spectrum of the light emitting device, the emission peak wavelength having the maximum emission intensity is preferably in the range of 570 nm to 680 nm, and may be in the range of 575 nm to 680 nm, or may be in the range of 575 nm to 670 nm. The range of the emission peak wavelength having the maximum emission intensity in the emission spectrum of the light emitting device may overlap with the range of the emission peak wavelength of the first phosphor. In the emission spectrum of the light emitting device, the emission peak wavelength having the maximum emission intensity may be due to the emission of the first phosphor.

Light-emitting element The light-emitting element has an emission peak wavelength in the range of 400 nm to 490 nm. The emission peak wavelength of the light-emitting element is preferably in the range of 420 nm to 480 nm, and may be in the range of 440 nm to 460 nm. The light-emitting device emits light with a correlated color temperature of 1950 K or less, which is warm and gives a sense of a calm atmosphere, by mixing the emission of the light-emitting element with the emission of the first phosphor and, if necessary, the emission of the second phosphor. At least a part of the emission of the light-emitting element is used as excitation light for the first phosphor, and in the case where the second phosphor is included, it is used as excitation light for the second phosphor. In addition, a part of the emission of the light-emitting element is used as light emitted from the light-emitting device. In the emission spectrum of the light-emitting element, the full width at half maximum of the emission spectrum having the emission peak wavelength is preferably 30 nm or less, more preferably 25 nm or less, and even more preferably 20 nm or less. For example, it is preferable to use a semiconductor light-emitting element using a nitride-based semiconductor as the light-emitting element. This makes it possible to obtain a stable light-emitting device that is highly efficient, has high linearity of output relative to input, and is resistant to mechanical shock.

First phosphor The light emitting device includes a first phosphor having an emission peak wavelength in the range of 570 nm to 680 nm. The first phosphor is excited by the emission of a light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm, and emits light having an emission peak wavelength in the range of 570 nm to 680 nm. The first phosphor may have an emission peak wavelength in the range of 575 nm to 670 nm, or may have an emission peak wavelength in the range of 580 nm to 660 nm. In the emission spectrum of the first phosphor, the full width at half maximum of the emission spectrum having the emission peak wavelength is preferably in the range of 3 nm to 120 nm. In the emission spectrum of the first phosphor, the full width at half maximum of the emission spectrum having the emission peak wavelength is preferably in the range of 3 nm to 15 nm, or in the range of 60 nm to 120 nm. In order to emit light having a correlated color temperature that gives a sense of warmth and a calm atmosphere from the light emitting device, the full width at half maximum of the emission spectrum having the emission peak wavelength of the first phosphor is preferably within the above range.

The first phosphor preferably includes at least one selected from the group consisting of a first nitride phosphor having a composition represented by the following formula (1A), a second nitride phosphor having a composition represented by the following formula (1B), a first fluoride phosphor represented by the following formula (1C), and a second fluoride phosphor having a composition represented by the following formula (1C') which is different in composition from the following formula (1C). The first phosphor preferably includes a first nitride phosphor having a composition represented by the following formula (1A) as an essential component. By including the first phosphor, the light emitting device can emit light having a correlated color temperature of 1950K or less, an emission spectrum showing the maximum emission intensity in the emission spectrum of the light emitting device having a full width at half maximum of 110 nm or less, and a melanopic ratio MR of 0.233 or less.
^M12Si5N8 _{: Eu} ( _1A )
(In formula (1A), ^M1 is an alkaline earth metal element including at least one selected from the group consisting of Ca, Sr, and Ba.)
_{SrqCasAltSiuNv : Eu} ( _{1B )}
(In formula (1B), q, s, t, u, and v respectively satisfy 0≦q<1, 0<s≦1, q+s≦1, 0.9≦t≦1.1, 0.9≦u≦1.1, and 2.5≦v≦3.5.)
A _c [M ² _1-b Mn ⁴⁺ _b F _d ] (1C)
(In formula (1C), A includes at least one selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , among which K ⁺ is preferred. ^{M 2} includes at least one element selected from the group consisting of Group 4 elements and Group 14 elements, among which Si and Ge are preferred. b satisfies 0<b<0.2, c is the absolute value of the charge of the [M ² _1-b Mn ⁴⁺ _b F _d ] ion, and d satisfies 5<d<7.)
A'_c' [M ² '_1-b' Mn ^{4 +} _b' F _d' ] (1C')
(In formula (1C'), A' includes at least one selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , among which K ⁺ is preferred. M ² ' includes at least one element selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, among which Si and Al are preferred. b' satisfies 0<b'<0.2, c' is the absolute value of the charge of the [M ² '_1-b' Mn ⁴⁺ _b' F _d' ] ion, and d' satisfies 5<d'<7.)
In this specification, in the formula expressing the composition of a phosphor, the part before the colon (:) expresses the molar ratio of each element in 1 mole of the host crystal and phosphor composition, and the part after the colon (:) expresses an activator element.

The first phosphor preferably includes at least one selected from the group consisting of a first nitride phosphor having a composition represented by the formula (1A), a second nitride phosphor having a composition represented by the formula (1B), a first fluoride phosphor represented by the formula (1C), and a second fluoride phosphor having a composition represented by the formula (1C') which is different from the formula (1C), a fluorogermanate phosphor having a composition represented by the formula (D), a fourth nitride phosphor having a composition represented by the formula (1E), and a first sulfide phosphor having a composition represented by the formula (1F), as described below. The first phosphor may include one type of phosphor alone, or may include two or more types of phosphors.

The light emitting device of the second embodiment includes a first nitride phosphor having a composition represented by the formula (1A) as the first phosphor. By including the first nitride phosphor having a composition represented by the formula (1A) as the first phosphor, it is possible to emit light having a correlated color temperature of 1950K or less, a full width at half maximum of an emission spectrum showing the maximum emission intensity in the emission spectrum of the light emitting device being 110 nm or less, and a melanopic ratio MR derived from the formula (1) being 0.233 or less. The light emitting device of the second embodiment preferably includes at least one type selected from the group consisting of a second nitride phosphor having a composition represented by the formula (1B) and a fluoride phosphor having a composition represented by the formula (1C) as the first phosphor.

The first phosphor may include at least one phosphor selected from the group consisting of a fluorogermanate phosphor, a fourth nitride phosphor, and a first sulfide phosphor. The fluorogermanate phosphor has a composition represented by the following formula (1D), for example. The fourth nitride phosphor has a composition represented by the following formula (1E), for example. The first sulfide phosphor has a composition represented by the following formula (1F), for example.
(i-j) MgO. (j/2) _{Sc2O3 . kmGgF2 . mCaF2} . (1-n) GeO2 _. (n/ ₂ ) ^M32O3 : Mn (1D)
(In formula (1D), ^M3 is at least one selected from the group consisting of Al, Ga, and In. i, j, k, m, n, and z each satisfy 2≦i≦4, 0≦j<0.5, 0<k<1.5, 0≦m<1.5, and 0≦n<0.5.)
^M4v2M5w2Al3 _{- y2Siy2Nz2 : M6 (} ^{1E )}
(In formula (1E), ^M4 is at least one element selected from the group consisting of Ca, Sr, Ba, and Mg, ^M5 is at least one element selected from the group consisting of Li, Na, and K, ^M6 is at least one element selected from the group consisting of Eu, Ce, Tb, and Mn, and v2, w2, y2, and z2 satisfy 0.80≦v2≦1.05, 0.80≦w2≦1.05, 0≦y2≦0.5, and 3.0≦z2≦5.0, respectively.)
(Ca,Sr)S:Eu (1F)
In this specification, in a formula showing the composition of a phosphor, a plurality of elements separated by a comma (,) means that at least one of these plurality of elements is contained in the composition, and a combination of two or more of the plurality of elements may be contained.

The fluorogermanate phosphor having the composition represented by formula (1D) may have a composition represented by the following formula (1d):
_{3.5MgO.0.5MgF2.GeO2} : _Mn (1d)

The fourth nitride phosphor having the composition represented by formula (1E) may have a composition represented by the following formula (1e):
M ⁴ _v2 M ⁵ _w2 M ⁶ _x2 Al _3-y2 Si _y2 N _z2 (1e)
(In formula (1e), ^M4 , ^M5 and ^M6 are respectively defined as ^M4 , ^M5 and ^M6 in formula (1E), v2, w2, y2 and z2 are respectively defined as v2, w2, y2 and z2 in formula (1E), and x2 satisfies 0.001<x2≦0.1.)

The fluorogermanate phosphor, the fourth nitride phosphor, and the first sulfide phosphor have an emission peak wavelength in the range of 570 nm to 680 nm, and preferably have an emission peak wavelength in the range of 600 nm to 630 nm. In the emission spectrum of the first phosphor, the fluorogermanate phosphor, the fourth nitride phosphor, and the first sulfide phosphor have a full width at half maximum of an emission spectrum having an emission peak wavelength of, for example, 5 nm to 100 nm, and preferably 6 nm to 90 nm.

The light emitting device of the first embodiment and the light emitting device of the second embodiment may contain one type of first phosphor alone, or may contain two or more types of first phosphors. By containing the first phosphor, the light emitting device has a correlated color temperature that gives a feeling of warmth, and emits light with a calm atmosphere.

When the first phosphor essentially contains a first nitride phosphor having a composition represented by formula (1A), all of the first phosphors may be the first nitride phosphor. When the first phosphor essentially contains a first nitride phosphor having a composition represented by formula (1A) and contains a first phosphor other than the first nitride phosphor having a composition represented by formula (1A), the mass ratio of the first nitride phosphor in the first phosphor to the first phosphor other than the first nitride phosphor (first nitride phosphor/first phosphor other than the first nitride phosphor) may be in the range of 99/1 to 1/99, 98/2 to 10/90, or 95/5 to 30/70. The first phosphor other than the first nitride phosphor having a composition represented by formula (1A) refers to at least one phosphor selected from the group consisting of a second nitride phosphor having a composition represented by formula (1B), a first fluoride phosphor represented by formula (1C), a second fluoride phosphor represented by formula (1C'), a fluorogermanate phosphor having a composition represented by formula (1D), a fourth nitride phosphor having a composition represented by formula (1E), and a first sulfide phosphor represented by formula (1F).

The light emitting device of the first embodiment or the light emitting device of the second embodiment may contain, as a first phosphor, at least one selected from the group consisting of a fluorogermanate phosphor having a composition represented by formula (1D), a fourth nitride phosphor having a composition represented by formula (1E), and a first sulfide phosphor having a composition represented by formula (1F). The first phosphor may contain one type of phosphor alone, or may contain two or more types of phosphors.

The content of the first phosphor contained in the light emitting device varies depending on the form of the light emitting device. When the first phosphor is contained in the wavelength conversion member of the light emitting device, it is preferable that the wavelength conversion member contains a phosphor and a translucent material. The wavelength conversion member may be provided with a wavelength conversion body containing a phosphor and a translucent material. The phosphor contained in the wavelength conversion member may have a total amount of phosphor of 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, or 50 parts by mass or more, per 100 parts by mass of the translucent material. It may also be 900 parts by mass or less, 800 parts by mass or less, 700 parts by mass or less, 600 parts by mass or less, 500 parts by mass or less, or 400 parts by mass or less. The total amount of phosphor refers to the total amount of the first phosphor when the light emitting device contains only the first phosphor and does not contain any other phosphor other than the first phosphor. The total amount of phosphor refers to the combined amount of the first phosphor and the second phosphor when the light emitting device contains a first phosphor and a second phosphor.

When the light emitting device includes a second phosphor described later, the content of the first phosphor contained in the light emitting device is preferably in the range of 5% by mass to 95% by mass with respect to the total amount of the first phosphor and the second phosphor. If the content of the first phosphor contained in the light emitting device is in the range of 5% by mass to 95% by mass with respect to the total amount of the first phosphor and the second phosphor, the light emitting device has a correlated color temperature of 1950K or less, a full width at half maximum of the emission spectrum showing the maximum emission intensity is 110 nm or less in the emission spectrum of the light emitting device, and a melanopic ratio MR is 0.233 or less, which gives a sense of warmth, and emits light with a calm atmosphere. The content of the first phosphor contained in the light emitting device may be in the range of 8% by mass to 80% by mass with respect to the total amount of the first phosphor and the second phosphor, or may be in the range of 10% by mass to 70% by mass with respect to the total amount of the first phosphor and the second phosphor, or may be in the range of 11% by mass to 60% by mass with respect to the total amount of the first phosphor and the second phosphor.

Second phosphor The light emitting device preferably includes a second phosphor having an emission peak wavelength in the range of 480 nm to less than 570 nm. The second phosphor preferably has an emission peak wavelength in the range of 480 nm to 569 nm. The second phosphor is excited by the emission of a light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm, and emits light having an emission peak wavelength in the range of 480 nm to less than 570 nm. The second phosphor is excited by the light emitting element and may have an emission peak wavelength in the range of 490 nm to 565 nm, or may have an emission peak wavelength in the range of 495 nm to 560 nm. The second phosphor is preferably such that the full width at half maximum of the emission spectrum having an emission peak wavelength in the emission spectrum of the second phosphor is in the range of 20 nm to 125 nm, may be in the range of 25 nm to 124 nm, or may be in the range of 30 nm to 123 nm. In order to emit light having a correlated color temperature that gives a feeling of warmth and creating a calm atmosphere, the full width at half maximum of the emission spectrum having an emission peak wavelength in the emission spectrum of the second phosphor is preferably within the range of 20 nm to 125 nm.

It is preferable that the second phosphor contains at least one selected from the group consisting of a rare earth aluminate phosphor having a composition represented by the following formula (2A) and a third nitride phosphor having a composition represented by the following formula (2B):
^Ln13 ( _{Al1 -aGaa ) 5O12 :} Ce(2A)
(In formula (2A), Ln ¹ is at least one element selected from the group consisting of Y, Gd, Tb, and Lu, and a satisfies 0≦a≦0.5.)
_{LawLn2xSi6Ny : Cez ( 2B} ⁾
(In formula (2B), ^Ln2 essentially contains at least one selected from the group consisting of Y and Gd, and may contain at least one selected from the group consisting of Sc and Lu, and when the ^Ln2 element contained in 1 mole of the composition is 100 mol%, the total of Y and Gd contained in ^Ln2 is 90 mol% or more, and w, x, y, and z satisfy 1.2≦w≦2.2, 0.5≦x≦1.2, 10≦y≦12.0, 0.5≦z≦1.2, 1.80<w+x<2.40, and 2.9≦w+x+z≦3.1.)
The rare earth aluminate phosphor having a composition represented by formula (2A) and the third nitride phosphor having a composition represented by formula (2B) have an emission peak having an emission peak wavelength in the emission spectrum of the phosphor, and a full width at half maximum of the emission peak is, for example, 90 nm or more, preferably 100 nm or more, and more preferably 110 nm or more, and for example, 125 nm or less, preferably 124 nm or less, and more preferably 123 nm or less.

The second phosphor may include at least one phosphor selected from the group consisting of alkaline earth metal aluminate phosphors and alkaline earth metal halosilicate phosphors. The alkaline earth metal aluminate phosphor is, for example, a phosphor that contains at least strontium and is activated with europium, and has, for example, a composition represented by the following formula (2C). The alkaline earth metal halosilicate phosphor is, for example, a phosphor that contains at least calcium and chlorine, and is activated with europium, and has, for example, a composition represented by the following formula (2D).
_{Sr4Al14O25 :} Eu ( _2C )
(Ca,Sr,Ba) _8MgSi4O16 (F,Cl _, Br) ₂ :Eu ( _2D )
In formula (2C), a part of Sr may be substituted with at least one element selected from the group consisting of Mg, Ca, Ba and Zn.
The alkaline earth metal aluminate phosphor having a composition represented by formula (2C) and the alkaline earth metal halosilicate phosphor having a composition represented by formula (2D) have an emission peak wavelength in the range of 480 nm or more and less than 520 nm, and preferably have an emission peak wavelength in the range of 485 nm or more and 515 nm or less.
In the alkaline earth metal aluminate phosphor having a composition represented by formula (2C) and the alkaline earth metal halosilicate phosphor having a composition represented by formula (2D), the full width at half maximum of an emission peak having an emission peak wavelength in the emission spectrum of the phosphor is, for example, 30 nm or more, preferably 40 nm or more, more preferably 50 nm or more, and for example, 80 nm or less, preferably 70 nm or less.

The second phosphor may include at least one phosphor selected from the group consisting of a β-sialon phosphor, a second sulfide phosphor, a scandium-based phosphor, and an alkaline earth metal silicate-based phosphor. The β-sialon phosphor has a composition represented by the following formula (2E), for example. The second sulfide phosphor has a composition represented by the following formula (2F), for example. The scandium-based phosphor has a composition represented by the following formula (2G), for example. The alkaline earth metal silicate-based phosphor has a composition represented by the following formula (2H) or a composition represented by the following formula (2I).
_{Si6- gAlgOgN8 -g :} Eu(0<g≦4.2) (2E)
(Sr, ^M7 ) _{Ga2S4 :} Eu(2F)
(In formula (2F), ^M7 is at least one element selected from the group consisting of Be, Mg, Ca, Ba, and Zn.)
(Ca,Sr) _{Sc2O4 :} Ce (2G)
(Ca,Sr) ₃ (Sc,Mg) _{2Si3O12 :} Ce( _2H )
(Ca,Sr,Ba) _2SiO4 :Eu( _2I )

The β-sialon phosphor, the second sulfide phosphor, the scandium-based phosphor, and the alkaline earth metal silicate-based phosphor have an emission peak wavelength in the range of 520 nm or more and less than 580 nm, and preferably have an emission peak wavelength in the range of 525 nm or more and 565 nm or less. In the emission spectrum of the β-sialon phosphor, the second sulfide phosphor, the scandium-based phosphor, and the alkaline earth metal silicate-based phosphor, the full width at half maximum of the emission spectrum having an emission peak wavelength in the emission spectrum of the second phosphor is, for example, 20 nm or more, preferably 30 nm or more, and, for example, 120 nm or less, preferably 115 nm or less.

The second phosphor may include at least one phosphor selected from the group consisting of a rare earth aluminate phosphor having a composition represented by formula (2A), a third nitride phosphor having a composition represented by formula (2B), an alkaline earth metal aluminate phosphor having a composition represented by formula (2C), an alkaline earth metal halosilicate phosphor having a composition represented by formula (2D), a β-sialon phosphor having a composition represented by formula (2E), a second sulfide phosphor having a composition represented by formula (2F), a scandium-based phosphor having a composition represented by formula (2G), an alkaline earth metal silicate-based phosphor having a composition represented by formula (2H), and an alkaline earth metal silicate-based phosphor having a composition represented by formula (2I). The second phosphor may include one type of phosphor alone or two or more types.

It is preferable that the light emitting device emits light with a color deviation Duv, which is the deviation from the black body radiation locus, of minus (-) 0.008 or more and plus (+) 0.008 or less. The color deviation Duv is the deviation of the light emitted from the light emitting device from the black body radiation locus, and is measured in accordance with JIS Z8725. Even if the correlated color temperature is relatively low, such as 1950K or less, if the color deviation Duv from the black body radiation locus (Duv is 0.000) on the CIE1931 chromaticity diagram is within the range of -0.008 to +0.008, the color of the irradiated object is natural, and light that is unlikely to cause discomfort to humans is emitted from the light emitting device. The light emitting device preferably emits light with a color deviation Duv, which is the deviation from the blackbody radiation locus at 1950K or less, in the range of -0.008 to +0.008, more preferably emits light with a Duv in the range of -0.006 to +0.006, and even more preferably emits light with a Duv in the range of -0.003 to +0.003. If light is emitted with a color deviation Duv, which is the deviation from the blackbody radiation locus at 1950K or less, that exceeds 0.008, the irradiated object may deviate from its natural color, causing people to feel uncomfortable.

Figure 2 shows the spectrum locus on the CIE 1931 chromaticity diagram, the black body radiation locus (Duv is 0.000) in the pure violet locus, and the color deviation from the black body radiation locus. Figure 3 shows an enlarged view of a part of Figure 2, and shows the black body radiation locus in the range of chromaticity coordinate x value from 0.300 to 0.600 and y value from 0.250 to 0.500 in the CIE 1931 chromaticity diagram, and the locus of Duv -0.020, Duv -0.010, Duv -0.008, Duv +0.008, Duv +0.010, and Duv +0.020, which are color deviations from the black body radiation locus at each correlated color temperature. In Figures 2 and 3, the straight lines that intersect with the blackbody radiation locus (Duv is 0.000) are iso-color temperature lines at each correlated color temperature (CCT is 1700K, 1950K, 2000K, 2700K, 3000K, 4000K, 5000K, 6500K). When Duv, which is the color deviation of the mixed color light emitted from the light-emitting device, is 0, there is no deviation from the blackbody radiation locus and it approximates the blackbody radiation locus.

It is preferable that the light emitting device emits light in which the second radiance in the range of 650 nm to 750 nm is 50% or less relative to the first radiance of 100% in the range of 400 nm to 750 nm. In the light emission of the light emitting device, the ratio of the second radiance in the range of 650 nm to 750 nm to the first radiance of 100% in the range of 400 nm to 750 nm is also called Lp. When the ratio Lp of the second radiance to the first radiance of the light emitted from the light emitting device is 50% or less, the light of the long-wavelength red component that is difficult for humans to sense is relatively small among the mixed light emitted from the light emitting device, so that the light emitted from the light emitting device has a warmth and gives a sense of a calm atmosphere without reducing the luminance. The ratio Lp of the second radiance to the first radiance of the light emitted from the light emitting device may be 45% or less, 40% or less, 35% or less, or 30% or less. The ratio Lp of the second radiance to the first radiance of the light emitted by the light emitting device may be 5% or more, or 8% or more, in order to emit light with good color rendering properties.

The ratio Lp of the second radiance to the first radiance of the light emitted by the light emitting device is calculated by the following formula (3). The ratio Lp of the second radiance in the range of 650 nm to 750 nm to the first radiance of 100% in the range of 400 nm to 750 nm of the light emitted by the light emitting device indicates the ratio of light of the long wavelength red component in the mixed color light emitted from the light emitting device.

The light emitting device preferably emits light having a relative melanopic ratio MR/MR ₀ of 99% or less. The relative melanopic ratio MR/MR ₀ refers to the ratio of the melanopic ratio MR derived from the above formula (1) of a light emitting device emitting light having a correlated color temperature of 1950K or less, when the reference melanopic ratio MR ₀ of a light emitting device emitting light having a correlated color temperature of more than 1950K is taken as 100%. The reference melanopic ratio MR ₀ can be the lowest melanopic ratio among the light emitting devices to be measured that emit light having a correlated color temperature of more than 1950K. When the relative melanopic ratio MR/MR ₀ is as small as 99% or less, light _that promotes melatonin secretion and naturally induces sleep can be emitted from the light emitting device. When light having a relative melanopic ratio MR/MR ₀ of less than 10% is emitted from the light-emitting device, for example, when a light-emitting device has a relative melanopic ratio MR/MR ₀ of 9% or less, the effect of secreting melatonin is greater than that of a light-emitting device that emits light with a correlated color temperature of more than 1950K, but the color balance of the light is disrupted and color rendering is reduced. For example, even for lighting used in private spaces such as living rooms and bedrooms, in order to irradiate light that satisfies the color rendering required of the light-emitting device and gives a warm and calm atmosphere, it is preferable that the light-emitting device emits light having a relative melanopic ratio MR/MR ₀ in the range of 10% to 99%. A light-emitting device that emits light with a correlated color temperature of 1950K or less may have a relative melanopic ratio MR/MR ₀ in the range of 10% to 99%, or in the range of 30% to 98%, or in the range of 40% to 96%.

The reference melanopic ratio MR ₀ of a light emitting device that emits light with a correlated color temperature exceeding 1950 K can be derived by the following formula (4).

(In formula (4), MR ₀ is the melanopic ratio of a light-emitting device having a correlated color temperature of more than 1950 K, S ₀ (λ) is the spectral radiance of light emitted from a light-emitting device having a correlated color temperature of more than 1950 K, and V(λ) and R _m (λ) are defined as in formula (1).)

The relative melanopic ratio MR/MR ₀ (%) can be calculated by the following formula (5).

An example of a light-emitting device will be described with reference to the drawings. Figures 4 and 5 are schematic cross-sectional views showing a light-emitting device of a first configuration example.

As shown in FIG. 4, the light emitting device 100 includes a light emitting element 10 having an emission peak wavelength in the range of 400 nm to 490 nm, and a first phosphor 71 that emits light when excited by light from the light emitting element.

The light emitting device 100 includes a molded body 41, a light emitting element 10, and a wavelength conversion member 21. The molded body 40 is formed by integrally molding a first lead 2, a second lead 3, and a resin part 42 containing a thermoplastic resin or a thermosetting resin. The molded body 41 forms a recess having a bottom surface and a side surface, and the light emitting element 10 is placed on the bottom surface of the recess. The light emitting element 10 has a pair of positive and negative electrodes, and the pair of positive and negative electrodes are electrically connected to the first lead 2 and the second lead 3 via wires 60, respectively. The light emitting element 10 is covered with a wavelength conversion member 21. The wavelength conversion member 21 includes, for example, a phosphor 70 that converts the wavelength of light from the light emitting element 10 and a translucent material. The wavelength conversion member 21 also functions as a sealing member that covers the light emitting element 10 and the phosphor 70 in the recess of the molded body 40. The phosphor 70 includes a first phosphor 71 that is excited by light from the light emitting element and has an emission peak wavelength in the range of 570 nm to 680 nm. The first lead 2 and the second lead 3 connected to a pair of positive and negative electrodes of the light emitting element 10 have portions exposed toward the outside of the package that constitutes the light emitting device 100. Power can be supplied from the outside via the first lead 2 and the second lead 3 to cause the light emitting device 100 to emit light.

As shown in FIG. 5, the light emitting device 200 is the same as the light emitting device 100 shown in FIG. 4, except that the phosphor 70 includes a second phosphor 72 having an emission peak wavelength in the range of 480 nm to 570 nm, and the same components are denoted by the same reference numerals.

The wavelength conversion member in the light emitting device of the first configuration example includes a phosphor and a light-transmitting material, and the light-transmitting material is preferably a resin. The light-transmitting material used in the wavelength conversion member is at least one selected from the group consisting of resin, glass, and inorganic material. The resin is preferably at least one selected from the group consisting of epoxy resin, silicone resin, phenolic resin, and polyimide resin. The inorganic material is at least one selected from the group consisting of aluminum oxide and aluminum nitride. In addition to the phosphor and the light-transmitting material, the wavelength conversion member may contain a filler, a colorant, and a light diffusing material as necessary. Examples of the filler include silicon dioxide, barium titanate, titanium oxide, and aluminum oxide. The content of other components other than the phosphor and the light-transmitting material contained in the wavelength conversion member can be in the range of 0.01 parts by mass to 50 parts by mass, or in the range of 0.1 parts by mass to 45 parts by mass, or in the range of 0.5 parts by mass to 40 parts by mass, based on 100 parts by mass of the light-transmitting material, in terms of the total content of the other components.

A method for manufacturing a light emitting device according to a first configuration example will be described. For details, the disclosure of JP 2010-62272 A can be referred to. The method for manufacturing a light emitting device preferably includes a molded body preparation step, a light emitting element arrangement step, a wavelength conversion member composition arrangement step, and a resin package formation step. When an aggregate molded body having a plurality of recesses is used as the molded body, a singulation step of separating the molded body into resin packages of each unit area may be included after the resin package formation step.

In the step of preparing a molded body, a plurality of leads are integrally molded using a thermosetting resin or a thermoplastic resin to prepare a molded body having a recess having a side surface and a bottom surface. The molded body may be a molded body made of an aggregate base including a plurality of recesses.
In the step of arranging the light-emitting element, the light-emitting element is arranged on the bottom surface of the recess of the molded body, and the positive and negative electrodes of the light-emitting element are connected to the first lead and the second lead by wires.
In the step of placing the composition for a wavelength conversion member, the composition for a wavelength conversion member is placed in the recess of the molded body.
In the resin package molding step, the composition for wavelength conversion material arranged in the recess of the molded body is cured to form a resin package, and a light emitting device is manufactured. When a molded body made of an aggregate base having a plurality of recesses is used, after the resin package forming step, the aggregate base having a plurality of recesses is separated into each resin package of each unit area in the singulation step, and individual light emitting devices are manufactured. In this manner, the light emitting device of the first configuration example shown in FIG. 4 or FIG. 5 can be manufactured.

Figure 6 is a schematic perspective view showing a light-emitting device of the second configuration example. Figure 7 is a schematic cross-sectional view showing a light-emitting device of the second configuration example.

As shown in Figs. 6 and 7, the light emitting device 300 comprises a support 1, a light emitting element 10 arranged on the support 1, a wavelength conversion member 22 including a phosphor 70 arranged on the upper surface of the light emitting element 10, and a light reflecting member 43 arranged on the support 1 to the side of the wavelength conversion member 22 and the light emitting element 10. A sealing member 50 is provided on the upper surface of the wavelength conversion member 22. The sealing member 50 has a lens portion 51 that is circular in a plan view and semispherical in a cross section, and a flange portion 52 that extends to the outer periphery of the lens portion 51. The lens portion 51 is circular in a plan view and semispherical in a cross section. The flange portion 52 also extends to the outer periphery of the lens portion 51.

The wavelength conversion member 22 is formed larger than the light emitting element 10 in a plan view. In addition, a first light-transmitting member 30 is provided between the side surface of the light emitting element 10 and the light reflecting member 43, the first light-transmitting member 30 being in contact with the side surface of the light emitting element 10 and a part of the wavelength conversion member 22. The first light-transmitting member 30 includes a light-transmitting joining member 32 provided between the light emitting element 10 and the wavelength conversion member 22. The light-transmitting joining member 32 can be an adhesive material that joins the light emitting element 10 and the wavelength conversion member 22. A part of the light-transmitting joining member 32 may be extended to a corner formed by the side surface of the light emitting element 10 and the main surface of the wavelength conversion member 22 on the light emitting element 10 side. In addition, as shown in FIG. 7, the cross-sectional shape of the extended light-transmitting joining member 32 can be an inverted triangle that spreads in the direction of the light reflecting member 43. The first light-transmitting member 30 and the joining member 32 can be made of a resin having light transmittance. The support 1 is a member for mounting the light emitting element 10, the sealing member 50, etc. on the upper surface. The support 1 includes an insulating base material and a conductive member 4 such as a wiring pattern for mounting a light-emitting element on the surface of the base material. The light reflecting member 43 is a member for covering the first light-transmitting member 30, the bonding member 32, and the wavelength conversion member 22. For details of the light-emitting device of the second configuration example and the manufacturing method of the light-emitting device of the second configuration example described later, the disclosure of JP 2020-57756 A can be referred to, for example.
There are.

The wavelength conversion member of the light emitting device of the second configuration example may be a single phosphor layer including a phosphor and a light-transmitting material, similar to the wavelength conversion member of the light emitting device of the first configuration example. The phosphor includes a first phosphor excited by light from the light emitting element and having an emission peak wavelength in the range of 570 nm to 680 nm. The phosphor may include a second phosphor excited by light from the light emitting element and having an emission peak wavelength in the range of 480 nm to 570 nm. The light-transmitting material may be the same light-transmitting material as the light-transmitting material used for the wavelength conversion member of the light emitting device of the first configuration example. In addition to the phosphor and the light-transmitting material, the wavelength conversion member of the light emitting device of the second configuration example may include a filler, a colorant, and a light diffusing material as necessary, similar to the wavelength conversion member of the light emitting device of the first configuration example. When the wavelength conversion member is composed of a single phosphor layer containing a phosphor and a light-transmitting material, a phosphor layer composition containing a phosphor and a light-transmitting material can be cured to form a plate-, sheet- or layer-like shape in advance, and then diced into pieces of a size that can be arranged on the light-emitting element to form a plate-, sheet- or layer-like wavelength conversion member.

Figure 8 is a schematic cross-sectional view showing another example of a light-emitting device according to the second configuration example, and a partially enlarged view of the schematic cross-sectional view of the phosphor layer, the bandpass filter layer, and the second translucent member. The light-emitting device in Figure 8 differs from the light-emitting device shown in Figure 7 in that the wavelength conversion member uses a phosphor layer containing phosphor, a bandpass filter layer, and a second translucent member, but the other members of the light-emitting device are similar to those of the light-emitting device shown in Figure 7.

The light emitting device is provided with a wavelength conversion member including a phosphor layer containing a first phosphor on the light output side of the light emitting element, and a bandpass filter layer arranged on the light output side of the phosphor layer, and the bandpass filter layer has an average reflectance of 80% or more for light in a wavelength range of 380 nm to 495 nm, for example, a wavelength range of 380 nm to 494 nm, for light with an incident angle of 0 degrees to 30 degrees, and an average reflectance of 20% or less for light with a wavelength range of more than 580 nm to 780 nm, for example, a wavelength range of 581 nm to 780 nm. By providing a wavelength conversion member including the aforementioned bandpass filter layer, the light emitting device can suppress the components of light on the short wavelength side that tend to inhibit the secretion of melatonin, and can lower the melanopic ratio MR. It is more preferable that the bandpass filter layer has an average reflectance of 80% or more for light in a wavelength range of 380 nm to 495 nm, for light with an incident angle of 0 degrees to 30 degrees, and an average reflectance of 20% or less for light with a wavelength range of more than 525 nm to 780 nm. It is more preferable that the bandpass filter layer has an average reflectance of 80% or more for light in the wavelength range of 380 nm or more and less than 495 nm for light with an incident angle in the range of 0 degrees or more and 30 degrees or less, and an average reflectance of 20% or less for light in the wavelength range of more than 500 nm and less than 780 nm.

The spectral radiance S _b (λ) of the light emitting device in a specific wavelength range before the dielectric multilayer film as the bandpass filter layer is disposed is taken as 100%, and the ratio of the spectral radiance S _a (λ) of the light emitted in a specific wavelength range of the light emitting device after the dielectric multilayer film as the bandpass filter layer is disposed can be measured as the maintenance rate of the spectral components of the light emitting device equipped with the bandpass filter layer. The specific wavelength range can be, for example, a range of 300 nm to 800 nm. The maintenance rate of the spectral components in the range of 300 nm to 800 nm of the light emitting device equipped with the bandpass filter layer can be calculated by the following formula (6). The maintenance rate of the spectral components in the range of 300 nm to 800 nm of the light emitting device equipped with the bandpass filter layer is preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more. If the spectral component maintenance rate of the light emitting device with a bandpass filter layer is less than 40%, for example, if the spectral component maintenance rate of the light emitting device with a bandpass filter layer is 39% or less, some light of the emission spectrum of the emission color emitted from the light emitting device may be weak, resulting in an emission color that feels strange to humans. Also, if the spectral component maintenance rate of the light emitting device with a bandpass filter layer is less than 40%, the light reflected by the bandpass filter layer increases, and the components of the light that are wavelength converted by the phosphor decrease, which may result in a decrease in brightness. The spectral component maintenance rate of the light emitting device with a bandpass filter layer may be 100% or less, 95% or less, 92% or less, or 91% or less.

The light emitting device 400 includes a wavelength conversion member 26 including a phosphor layer 23 containing phosphor 70 and a bandpass filter layer 24. The wavelength conversion member 26 may include a second translucent member 25, or may be a laminate in which the phosphor layer 23, the bandpass filter layer 24, and the second translucent member 25 are laminated in this order from the light emission side of the light emitting element. The phosphor 70 included in the phosphor layer 23 may include a first phosphor and may include a second phosphor. The phosphor layer 23, the bandpass filter layer 24, and the second translucent member 25 may be in the form of a plate, sheet, or layer formed larger than the light emitting element 10 in a plan view, and the phosphor layer 23, the bandpass filter layer 24, and the second translucent member 25 are laminated in this order from the light emitting element 10 side to form the wavelength conversion member 26.

The bandpass filter layer 24 is preferably made of a dielectric multilayer film. The dielectric multilayer film can be, for example, a multilayer film in which a first dielectric layer 24a and a second dielectric layer 24b having different refractive indices are alternately stacked. The bandpass filter layer 24 can be configured to reflect light in a wavelength range of 380 nm to less than 495 nm for light with an incident angle of 0 degrees to 30 degrees and transmit light having an emission peak wavelength in a range of 570 nm to 680 nm emitted by the phosphor contained in the phosphor layer 23 by setting the film thickness of the first dielectric layer 24a and the film thickness of the second dielectric layer 24b based on the emission spectrum (center wavelength and intensity distribution for wavelength) of the light emitted by the light emitting element 10, and the first refractive index of the first dielectric layer 24a and the second refractive index of the second dielectric layer 24b. The bandpass filter layer 24 made of a dielectric multilayer film is formed by alternately and periodically forming two first dielectric layers 24a and second dielectric layers 24b having different refractive indices, each with a film thickness of λ/4. λ is the peak wavelength in the wavelength range to be reflected, and is the in-medium wavelength for each dielectric material. In the bandpass filter layer 24, the refractive indexes and refractive index difference of the first dielectric layer 24a made of a dielectric material with a low refractive index and the second dielectric layer 24b made of a dielectric material with a high refractive index, as well as the number of alternating periods, are appropriately set so that the desired average reflectance can be stably obtained in the desired wavelength range.

The refractive index (first refractive index) of the first dielectric layer having a low refractive index can be set, for example, in the range of 1.0 to 1.8, preferably in the range of 1.2 to 1.6. The first dielectric layer can be formed, for example, of SiO ₂ (refractive index, for example, 1.5). The refractive index (second refractive index) of the second dielectric layer having a high refractive index can be set, for example, in the range of 1.5 to 3.0, preferably in the range of 2.0 to 2.6. The second dielectric layer can be formed, for example, of Nb ₂ O ₅ (refractive index, for example, 2.4). The number of periods in which the first dielectric layer and the second dielectric layer are alternately formed can be set, for example, in the range of 1 to 30, preferably in the range of 1 to 25.

The dielectric material constituting the first dielectric layer can be selected from, for example, _SiO2 , _{Al2O3 , and SiON} . The dielectric material constituting the second dielectric layer can be selected from, for example, _{TiO2 , Nb2O3} , _Ta2O5 , and _Zr2O5 .

The phosphor layer may be a wavelength conversion member made of a single phosphor layer, and may be a similar phosphor layer. The light-transmitting member may be made of glass or resin. The glass may be selected from borosilicate glass or quartz glass, for example. The resin may be selected from silicone resin or epoxy resin, for example.

The wavelength conversion member including the phosphor layer, the bandpass filter layer, and the second light-transmissive member can be formed, for example, as follows.
First, a plate-shaped second light-transmitting member is prepared. Next, a first dielectric layer and a second dielectric layer having different refractive indices are alternately laminated to form a bandpass filter layer made of a dielectric multilayer film. The dielectric multilayer film can be formed by alternately depositing the first dielectric layer and the second dielectric layer by atomic layer deposition (ALD), sputtering, vapor deposition, or the like. Next, a phosphor layer is formed on the bandpass filter layer. The phosphor layer can be formed, for example, on the bandpass filter layer by using a printing method. In the printing method, a phosphor layer composition containing a phosphor, a binder, and, if necessary, a solvent is prepared, and the phosphor layer composition is applied to the surface of the bandpass filter layer made of a dielectric multilayer film and dried to form a phosphor layer. As the binder, an organic binder such as an epoxy resin, a silicone resin, a phenol resin, and a polyimide resin, or an inorganic binder such as glass can be used. The phosphor layer can be formed by a compression molding method, a phosphor electrodeposition method, a phosphor sheet method, or the like instead of the printing method.

A method for manufacturing the light emitting device of the second configuration example will be described. The method for manufacturing the light emitting device of the second configuration example includes a step of arranging the light emitting element, a step of preparing the wavelength conversion member, a step of forming the translucent member and the joining member, a step of arranging the light reflecting member, and a step of arranging the sealing member, and may also include a step of singulating into each unit area.

In the process of arranging the light-emitting element, the light-emitting element is flip-chip mounted on a support prepared in advance. In the process of preparing the wavelength conversion member, the wavelength conversion member formed in advance in a plate, sheet or layer shape by the above-mentioned method is divided into individual pieces in a size that can be arranged on the light-emitting element, to prepare a plate-shaped, sheet-shaped or layer-shaped wavelength conversion member. In the process of forming the first translucent member and the joining member, a translucent adhesive is applied to the upper surface of the light-emitting element, and the wavelength conversion member is joined to the upper surface of the light-emitting element. The adhesive that protrudes from the interface between the light-emitting element and the wavelength conversion member extends from the side of the light-emitting element to the periphery of the wavelength conversion member, and is hardened in a fillet shape to form the first translucent member and the joining member. In the process of arranging the light reflecting member, a white resin is arranged and hardened on the upper surface of the support so as to cover the side surfaces of the wavelength conversion member and the translucent member, and the light reflecting member is arranged. Finally, a sealing member is arranged on the upper surfaces of the wavelength conversion member and the light reflecting member. This allows the light-emitting device of the second configuration example to be manufactured.

1. Lighting fixture or lighting fixture The lighting fixture or lighting fixture may include at least one of the above-mentioned light-emitting devices. The lighting fixture or lighting fixture is configured with the above-mentioned light-emitting device, and may further include a reflecting member, a protective member, an accessory device for supplying power to the light-emitting device, and the like. The lighting fixture or lighting fixture may include a plurality of light-emitting devices. When the lighting fixture or lighting fixture includes a plurality of light-emitting devices, the lighting fixture or lighting fixture may include a plurality of identical light-emitting devices, or may include a plurality of light-emitting devices of different forms. In addition, the lighting fixture or lighting fixture may include a driving device that can individually drive the plurality of light-emitting devices to adjust the brightness of each light-emitting device. The lighting fixture or lighting fixture may be used in any of a direct-mount type, an embedded type, a hanging type, and the like. The lighting fixture may be a lighting fixture intended for outdoor installation such as a street light, a port, or a tunnel, or may be a lighting fixture intended for outdoor use such as a headlight, a flashlight, or a portable lantern using an LED, or may be a lighting fixture installed indoors or near the outdoors such as a window. The lighting fixture has an emission color that gives a feeling of warmth from the above-mentioned light-emitting device, is capable of emitting light that gives a feeling of calm, promotes the secretion of melatonin, and naturally induces sleep, and may be used as general indoor lighting, indirect lighting, or vehicle lighting in private spaces such as indoor living rooms and bedrooms.

The street light may be equipped with at least one of the above-mentioned light emitting devices. FIG. 9 is a diagram showing an example of a street light 1000. The street light 1000 includes a pole P installed on the sidewalk W or roadway C1 and a support part S for the light emitting device Le. The support part S includes a light transmitting part T that covers the periphery of the light emitting device Le and transmits at least a part of the light emitted by the light emitting device Le, such as acrylic, polycarbonate, or glass. The street light 1000 can illuminate low places from high places by the light emitting device Le installed on the support part S integrated with the pole P. The street light may be not only a pole-type street light equipped with a pole whose support part can be set to any height, but also a bracket-type street light in which the support part is supported by a bracket instead of a pole, a floodlight-type street light that illuminates from below to above, or a landscape material-embedded type street light that is incorporated into a landscape material such as a pillar or block.

The street light may be a low-position lighting device that illuminates the road surface from a low position. The low-position lighting device may be equipped with at least one of the above-mentioned light-emitting devices. When the above-mentioned light-emitting device is used in the low-position lighting device, a calm and warm light can be emitted. FIG. 10 is a diagram showing an example of a low-position lighting device 1001. The low-position lighting device 1001 may be installed on a mounting stand B provided on the side of the road C2, for example. The low-position lighting device can be installed at a position lower than the eye level of the driver of a vehicle traveling on the road, for example. The low-position lighting device may be set at a height of about 1 m to 1.2 m from the road surface, for example. The low-position lighting device may be installed not only on the side of the road, but also on the side of a flower bed or a park sidewalk.

The present invention will be described in detail below with reference to examples. The present invention is not limited to these examples.

The light emitting devices of each of the examples and comparative examples used the following first phosphor and/or second phosphor.

First phosphor As the first phosphor, first nitride phosphors BSESN-2 and BSESN-3 contained in the composition represented by formula (1A), second nitride phosphors SCASN-1, SCASN-2, SCASN-3, SCASN-4, and SCASN-6 contained in the composition represented by formula (1B), and fluoride phosphor KSF contained in the composition represented by formula (1C) were prepared. These phosphors are the first nitride phosphor or the second nitride phosphor contained in the composition represented by formula (1A) or formula (1B), but the molar ratios of each element contained in each composition are different, and as shown in Table 1, they have different emission peak wavelengths and full widths at half maximum.

Second phosphor As the second phosphor, G-YAG1 and G-YAG4, which are rare earth aluminate phosphors contained in the composition represented by formula (2A) and having a composition of Y ₃ (Al, Ga) ₅ O ₁₂ :Ce (a satisfies 0<a≦0.5), and YAG1 and YAG3, which are rare earth aluminate phosphors contained in the composition represented by formula (2A) and having a composition of Y ₃ Al ₅ O ₁₂ :Ce, were prepared. These phosphors are rare earth aluminate phosphors contained in the composition represented by formula (2A), but the molar ratios of the elements contained in each composition are different, and as shown in Table 2, they have different emission peak wavelengths and full widths at half maximum.

Measurement of emission spectrum of phosphor Each phosphor was irradiated with light having an excitation wavelength of 450 nm using a quantum efficiency measurement device (QE-2000, manufactured by Otsuka Electronics Co., Ltd.), and the emission spectrum at room temperature (about 25° C.) was measured, and the emission peak wavelength and full width at half maximum were measured from each emission spectrum. The results are shown in Tables 1 and 2.

Bandpass Filter Layer The bandpass filter layers made of the dielectric multilayer film-1 (DBR-1), dielectric multilayer film-2 (DBR-2) and dielectric multilayer film-3 (DBR-3) used in the examples can be used.

Measurement of the reflection spectrum of the dielectric multilayer film For each dielectric multilayer film, the light of the excitation light source was irradiated from the normal direction (incident angle 0 degrees) of the dielectric multilayer film, and the reflection spectrum in the wavelength range of 300 nm to 800 nm was measured at room temperature (25 ° C. ± 5 ° C.) using a spectrophotometer (V-670, manufactured by JASCO Corporation). The reflection spectra of the dielectric multilayer film-1 (DBR-1), the dielectric multilayer film-2 (DBR-2), and the dielectric multilayer film-3 (DBR-3) were measured. The reflection spectra of the dielectric multilayer film-1 (DBR-1), the dielectric multilayer film-2 (DBR-2), and the dielectric multilayer film-3 (DBR-3) are shown in FIG. 11. In the reflection spectrum of each dielectric layer at an incident angle of 0 degrees, the maximum reflection intensity in the wavelength range of 380 nm to 780 nm was taken as 100%. Table 3 shows the average reflectance of light in the wavelength range of 380 nm or more and less than 495 nm, the average reflectance of light in the wavelength range of more than 580 nm and less than 780 nm, the average reflectance of light in the wavelength range of 525 nm or more and less than 780 nm, and the average reflectance of light in the wavelength range of 500 nm or more and less than 780 nm, for light with an incident angle of 0 degrees.

Dielectric multilayer film-1 (DBR-1) had an average reflectance of 80% or more for light in the wavelength range of 380 nm or more and less than 495 nm, and an average reflectance of 20% or less for light in the wavelength range of more than 580 nm and less than 780 nm. In dielectric multilayer film-1 (DBR-1), dielectric multilayer film-2 (DBR-2), and dielectric multilayer film-3 (DBR-3), light in the wavelength range of 380 nm or more and less than 495 nm is, for example, light in the wavelength range of 380 nm or more and less than 494 nm. Moreover, light in the wavelength range of more than 580 nm and less than 780 nm is, for example, light in the wavelength range of 581 nm or more and less than 780 nm.
Dielectric multilayer film-2 (DBR-2) had an average reflectance of 80% or more for light in the wavelength range of 380 nm or more and less than 495 nm, and an average reflectance of 20% or less for light in the wavelength range of 525 nm or more and 780 nm or less.
Dielectric multilayer film-3 (DBR-3) had an average reflectance of 80% or more for light in the wavelength range of 380 nm or more and less than 495 nm, and an average reflectance of 20% or less for light in the wavelength range of 500 nm or more and 780 nm or less.

Examples 1 and 2
A light emitting device of the first configuration example was manufactured. For the light emitting device of the first configuration example, refer to FIG.
The light emitting element 10 used was a light emitting element 10 having a nitride-based semiconductor layer laminated thereon and having an emission peak wavelength of 450 nm. The size of the light emitting element 10 was a roughly square shape with a planar shape of approximately 700 mm on each side, and a thickness of approximately 200 mm.
A lead frame was used as the first lead 2 and the second lead 3, and the first lead 2 and the second lead 3 were integrally molded using epoxy resin to prepare a molded body 41 having a recess with side and bottom surfaces.
The light emitting element 10 was placed on the bottom surface of the recess of the molded body 41 , and the positive and negative electrodes of the light emitting element 10 were connected to the first lead 2 and the second lead 3 by wires 60 made of Au.
Silicone resin was used as the light-transmitting material constituting the wavelength conversion member 21. The composition for wavelength conversion member was blended with the first phosphor 71 and the second phosphor 72 so that the correlated color temperature of the mixed light of the light from the light-emitting element 10 and the light of the phosphor 70 including the first phosphor 71 and the second phosphor 72 was about 1800K to 1850K, which is 1950K or less. Here, the total amount of the phosphor 70 relative to 100 parts by mass of the light-transmitting material and the blending ratio of the first phosphor 71 and the second phosphor 72 are as shown in Table 4. The composition for wavelength conversion member was blended with 2 parts by mass of aluminum oxide as a filler relative to 100 parts by mass of silicone resin. Next, the prepared composition for wavelength conversion member was filled into the recess of the molded body 41.
The composition for the wavelength conversion member filled in the recess of the molded body 41 was heated at 150°C for 3 hours to harden it, forming a resin package equipped with a wavelength conversion member 21 including a first phosphor 71 and a second phosphor 72, thereby producing a first configuration example light emitting device 200 that emits light with a correlated color temperature of 1950K or less.

Example 3
A light emitting device of a first configuration example was manufactured. The light emitting device of the first configuration example includes only the first phosphor and does not include the second phosphor. See FIG.
As a composition for a wavelength conversion member, the first phosphor 71 shown in each example in Table 4 was used, and the first phosphor 71 was 100 mass% relative to the total amount of phosphor 70 (total amount of first phosphor 71) and the total amount of the first phosphor 71 and the second phosphor. A resin package was formed in the same manner as in Example 1, except that the first phosphor 71 was 100 mass%, and a light emitting device 100 of a first configuration example was manufactured, which emits light with a correlated color temperature of 1950 K or less. As shown in Table 4, as the first phosphor, a first nitride phosphor having a composition represented by formula (1A), two types of first nitride phosphors BSESN2 and BSESN3 having different compositions were used, and the mass ratio of BSESN2 to BSESN3 (BSESN2/BSESN3) was 30/70.

Example 4
The light emitting device 200 of the first configuration example was manufactured. The light emitting device 200 of the first configuration example includes a first phosphor 71 and a second phosphor 72. See FIG.
Phenyl silicone resin was used as the light-transmitting material constituting the wavelength conversion member 21. The phosphors shown in Table 4 were used as the first phosphor 71 and the second phosphor 72.
The composition for wavelength conversion members was prepared by blending first phosphor 71 and second phosphor 72 as shown in Table 4 with 100 parts by mass of the light-transmitting material so that the correlated color temperature of mixed light of light from light-emitting element 10 and light of phosphor 70 containing first phosphor 71 was approximately 1800 K to 1850 K, which is 1950 K or lower. The composition for wavelength conversion members was prepared by blending 15 parts by mass of silicon dioxide as a filler with 100 parts by mass of phenyl silicone resin. Next, the prepared composition for wavelength conversion members was filled into the recesses of molded body 41.
The composition for the wavelength conversion member filled in the recess of the molded body 41 was heated at 150°C for 4 hours to harden it, forming a resin package equipped with a wavelength conversion member 21 including a first phosphor 71 and a second phosphor 72, thereby producing a light emitting device 200 of a first configuration example that emits light having a correlated color temperature of 1950K or less.

Examples 5 and 6
A light emitting device of the first configuration example was manufactured in the same manner as in Example 1, and a dielectric multilayer film was arranged as a bandpass filter layer 24 on the light emission side of the wavelength conversion member 21 of the light emitting device 100 as shown in Fig. 12. In Example 5, a dielectric multilayer film 2 (DBR-2) was arranged on the light emission side of the wavelength conversion member of the light emitting device similar to Example 1. In Example 6, a dielectric multilayer film 3 (DBR-3) was arranged on the light emission side of the wavelength conversion member of the light emitting device similar to Example 1.

Examples 7 and 8
In Example 7, a dielectric multilayer film 2 (DBR-2) was disposed on the light emission side of the wavelength conversion member of the light emitting device similar to Example 2. In Example 8, a dielectric multilayer film 3 (DBR-3) was disposed on the light emission side of the wavelength conversion member of the light emitting device similar to Example 2.

Examples 9 and 10
In Example 9, a dielectric multilayer film 2 (DBR-2) was disposed on the light emission side of the wavelength conversion member of the light emitting device similar to Example 3. In Example 10, a dielectric multilayer film 3 (DBR-3) was disposed on the light emission side of the wavelength conversion member of the light emitting device similar to Example 3.

Examples 11 and 12
In Example 11, a dielectric multilayer film 2 (DBR-2) was disposed on the light emission side of the wavelength conversion member of the light emitting device similar to Example 4. In Example 12, a dielectric multilayer film 3 (DBR-3) was disposed on the light emission side of the wavelength conversion member of the light emitting device similar to Example 4.

Comparative Example 1
A light emitting device according to the second configuration example was manufactured. For the light emitting device according to the second configuration example, see Figs. 6 and 7.

Arrangement process of light-emitting element The support 1 was a ceramic substrate made of aluminum nitride. The light-emitting element 10 was a light-emitting element 10 in which a nitride-based semiconductor layer having an emission peak wavelength of 450 nm was laminated. The size of the light-emitting element 10 was a roughly square shape of about 1.0 mm square in plan view, and the thickness was about 0.11 mm. The light-emitting element was arranged so that the light-emitting surface was on the sealing member side, and flip-chip mounted by bumps using a conductive member 4 made of Au.

Wavelength conversion member preparation process Silicone resin was used as the light-transmitting material constituting the wavelength conversion member 22. The wavelength conversion member composition was mixed with the first phosphor and the second phosphor so that the correlated color temperature of the mixed light of the light from the light-emitting element 10 and the light of the phosphor 70 containing the first phosphor and the second phosphor was around 2230 K, which is close to the color temperature of a sodium lamp, relative to 100 parts by mass of the light-transmitting material. Here, the total amount of the phosphor 70 relative to 100 parts by mass of the light-transmitting material and the mixing ratio of the first phosphor and the second phosphor are as shown in Table 4. The wavelength conversion member composition was mixed with 2 parts by mass of aluminum oxide as a filler relative to 100 parts by mass of silicone resin. Next, the prepared wavelength conversion member composition was heated at 180° C. for 2 hours to harden it into a sheet shape, and a sheet-like wavelength conversion member 22 was prepared that was approximately 0.1 mm larger in length and width than the planar shape of the light-emitting element 10, had a planar shape of approximately 1.6 mm square, and had a thickness of approximately 150 μm.

Step of forming light-transmitting member and joining member A light-transmitting adhesive, phenyl silicone resin, was applied to the upper surface of the light-emitting element 10, and the wavelength conversion member 22 was joined thereto. Further, a light-transmitting adhesive was applied to the interface between the light-emitting element 10 and the wavelength conversion member 22 and cured at 150° C. for 4 hours to form a first light-transmitting member 30 and joining member 32 that were hardened in a fillet shape so as to extend from the side surface of the light-emitting element 10 to the periphery of the wavelength conversion member 22.

A composition for a light reflecting member was prepared, which contained dimethyl silicone resin and titanium oxide particles having an average particle size (catalog value) of 0.28 μm, and contained 60 parts by mass of titanium oxide particles per 100 parts by mass of dimethyl silicone resin. The composition for a light reflecting member, which is a white resin, was placed on the upper surface of the support 1 so as to cover the side surfaces of the wavelength conversion member 22 and the light-transmitting member 30, and was cured to form the light reflecting member 43.

Sealing member placement process Finally, a sealing member 50 was placed, which had a lens portion 51 that was formed by curing a phenyl silicone resin and was circular in a plan view and semispherical in a cross-sectional view, and a flange portion 52 that extended outward from the outer periphery of the lens portion 51, and the light-emitting device 300 of the second configuration example was manufactured. The light-emitting device 300 emits light with a correlated color temperature exceeding 1950 K.

Comparative Examples 2 and 3
A light emitting device of a first configuration example was manufactured. The light emitting device of the first configuration example includes a first phosphor and a second phosphor.
A wavelength conversion member composition was prepared containing a first phosphor 71 and a second phosphor 72 per 100 parts by mass of a phenyl silicone resin as a translucent material such that the correlated color temperature of mixed light of light from the light emitting element 10 and light of a phosphor 70 containing a first phosphor 71 and a second phosphor 72 was approximately 2000 K, which is close to the color temperature of a sodium lamp. In this wavelength conversion member composition, the total amount of phosphor 70 relative to 100 parts by mass of the translucent material and the blending ratio of the first phosphor 71 and the second phosphor 72 are as shown in Table 4.
The composition for the wavelength conversion member was injected onto the light emitting element 10 in the recess of the molded body 41 to fill the recess, and then heated at 150° C. for 4 hours to harden the composition for the fluorescent member and form the fluorescent member 21. In this manner, the light emitting device 200 of the first configuration example was manufactured, which emits light having a correlated color temperature exceeding 1950 K and not exceeding 2000 K.

The following measurements were performed on each light-emitting device. The results are shown in Tables 4 to 7.

Emission spectrum of the light-emitting device The emission spectrum of each light-emitting device was measured using a light measurement system combining a spectrophotometer (PMA-12, manufactured by Hamamatsu Photonics Co., Ltd.) and an integrating sphere. The emission spectrum of each light-emitting device was measured at room temperature (20°C to 30°C). Figures 13 to 18 show the emission spectrum (spectral radiance) S(λ) of each light-emitting device when the luminance derived from the denominator in the above formula (1) of each light-emitting device is set to an equivalent value, the CIE-defined human photopic standard luminous efficiency curve V(λ), and the CIE-defined ipRGC sensitivity curve R _m (λ). Figures 19 to 22 show the emission spectra of a light-emitting device without a bandpass filter layer and a light-emitting device with each bandpass filter layer.

Chromaticity coordinates (x, y), correlated color temperature (K), color deviation Duv, general color rendering index Ra, special color rendering index R9, and full width at half maximum From the emission spectrum of each light-emitting device, the chromaticity coordinates (x value, y value) on the CIE chromaticity diagram of CIE1931, the correlated color temperature (CCT: K) and color deviation Duv in accordance with JIS Z8725, and the general color rendering index Ra, special color rendering index R9, and full width at half maximum in accordance with JIS Z8726 were measured.

Ratio of second radiance to first radiance Lp
From the emission spectrum (spectral radiance) S(λ) of each light-emitting device, the proportion Lp (%) of the second radiance in the range of 650 nm or more and 750 nm or less was calculated based on the above formula (3) when the first radiance in the range of 400 nm or more and 750 nm or less was set to 100%.

Melanopic ratio MR
The emission spectrum (spectral radiance) S(λ) measured for each light-emitting device, the standard relative luminous efficiency curve V(λ) for human photopic vision defined by the CIE, and the sensitivity curve R _m (λ) for ipRGC defined by the CIE were inserted into the above formula (1), and the melanopic ratio MR for each light-emitting device was measured based on the above formula (1). For the standard relative luminous efficiency curve V(λ) for human photopic vision, an action curve was used in which the maximum sensitivity (peak sensitivity wavelength) was set to 1. For the sensitivity curve R _m (λ) for ipRGC defined by the CIE, an action curve was used in which the maximum sensitivity (peak sensitivity wavelength) was set to 1.

Relative melanopic ratio MR/MR ₀
Among the light emitting devices of Comparative Examples 1 to 3 that emit light with a correlated color temperature exceeding 1950 K, the melanopic ratio of the light emitting device of Comparative Example 3, which has the lowest melanopic ratio MR, was set as the reference melanopic ratio MR ₀ based on the above formula (4). The relative melanopic ratio MR/MR ₀ , which is the ratio of the melanopic ratio MR of each light emitting device to the reference melanopic ratio MR ₀ , was calculated based on the above formula (5).

Maintenance rate of spectral components when a bandpass filter layer is provided The maintenance rate (%) of spectral components when a bandpass filter layer is provided was calculated based on the above formula (6) as the ratio of the spectral radiance S _a (λ) of emission in the range of 300 nm or more and 800 nm or less of the light emitting device after the dielectric multilayer film serving as a bandpass filter layer is provided to the spectral radiance S _b (λ) of emission in the range of 300 nm or more and 800 nm or less of the light emitting device before the dielectric multilayer film serving as a bandpass filter layer is provided, which is taken as 100%.

As shown in Table 4 or Table 6, the light emitting devices according to Examples 1 to 12 had a correlated color temperature of 1950K or less, and emitted light with a warmth similar to that of a candle or a campfire flame. In addition, even when the light emitting devices are used as a replacement for high-pressure sodium lamps, the color of the irradiated object is natural, and light that is less likely to cause discomfort to humans is emitted. In addition, the light emitting devices according to Examples 1 to 12 had a full width at half maximum of the emission spectrum showing the maximum emission intensity in the range of 3 nm to 110 nm. In addition, the emission peak wavelength in the emission spectrum of the light emitting device was in the range of 570 nm to 680 nm. Since the full width at half maximum of the emission peak having the maximum emission intensity in the emission spectrum of the light emitting device was 3 nm to 110 nm, the light emitting device was able to suppress light components on the long wavelength side that are difficult for humans to sense. In addition, the light emitting devices according to Examples 1 to 12 emit light with a melanopic ratio MR of 0.233 or less, as calculated from the formula (1), and are believed to be able to irradiate light that promotes melatonin secretion without strongly stimulating human ipRGC, naturally induces sleep, and provide a sense of calm.

The light emitting devices according to Examples 1 to 4 emitted light with a color deviation Duv, which is the deviation from the blackbody radiation locus, of 0.000, and even when emitting light with a correlated color temperature of 1950 K or less, the color of the irradiated object was natural, and light that was unlikely to cause discomfort to humans was emitted from the light emitting devices.
The light emitting devices according to Examples 5 to 12, even when equipped with a dielectric multilayer film as a bandpass filter layer, emitted light with a color deviation Duv, which is the deviation from the blackbody radiation locus, of minus (-) 0.008 or more and plus (+) 0.008 or less, and the color of the irradiated object was natural, so that the light emitted from the light emitting device was unlikely to cause discomfort to humans.

As shown in Table 5 or Table 7, the light emitting devices according to Examples 1 to 12 emitted light in which the ratio Lp of the second radiance in the range of 650 nm to 750 nm to the first radiance of 100% in the range of 400 nm to 750 nm was 30% or less. The light emitting devices according to Examples 1 to 12 emitted mixed light from the light emitting devices with a relatively small amount of red light component on the long wavelength side, which is difficult for humans to detect, and therefore emitted light that gives a sense of a warm and calm atmosphere without reducing brightness.

The light-emitting devices according to Examples 1 to 12 had a relative melanopic ratio MR/MR ₀ of 40% or more and 99% or less, and were considered to be capable of emitting light from the light-emitting device that promotes melatonin secretion and naturally induces sleep without disrupting the color balance of the emitted color.

The light-emitting devices according to Examples 1, 2, 4, 5, 6, 7, 8, 11, and 12 had an average color rendering index Ra of 40 or more, and emitted light with color rendering that allowed light work to be performed without discomfort even when used in private spaces such as a living room or bedroom.

The light-emitting devices according to Examples 3, 9, and 10 have an average color rendering index Ra of 28 or more and 40 or less, and therefore have sufficient color rendering properties for use outdoors such as on roads, and emit light with a calming atmosphere without strongly stimulating the ipRGC, with a low melanopic ratio MR of 0.233 or less.

Even when the light emitting devices according to Examples 5 to 12 were provided with a dielectric multilayer film as a bandpass filter layer, they maintained 88% or more of the emission spectrum of a light emitting device that did not have a bandpass filter layer, and emitted light that made it easy for humans to see the irradiated object while reducing the short-wavelength light that tends to stimulate the ipRGC.

The light emitting devices according to Comparative Examples 1 to 3 emit light with a correlated color temperature slightly higher than that emitted by a candle or a high-pressure sodium lamp, and the melanopic ratio MR exceeds 0.233. It is believed that the light emitted is likely to stimulate ipRGC and suppress the secretion of melatonin.

As shown in Figures 13 to 16, the light emitting devices according to Examples 1 to 4 had a melanopic ratio MR of 0.233 or less, and emitted light with small short wavelength components that easily stimulate ipRGCs, while having a higher emission intensity than Comparative Example 3 in the wavelength range of 550 nm to 650 nm that is easily detected by humans, making it easier for humans to see the irradiated object.

As shown in Figures 17 and 18, the light-emitting devices according to Comparative Examples 1 to 3 had a melanopic ratio MR exceeding 0.233. Comparative Examples 1 and 2 had higher emission intensities on the short wavelength side, which is more likely to stimulate ipRGCs, than Comparative Example 3, which had the lowest melanopic ratio MR among the comparative examples, and tended to be more likely to inhibit melatonin secretion.

As shown in Figures 19 to 22, the light emitting devices according to Examples 5 to 12, even when equipped with a bandpass filter layer and suppressed emission of light on the short wavelength side, had high light emission intensity almost equivalent to that of a light emitting device not equipped with a bandpass filter layer, and emitted light that allowed humans to easily see the irradiated object.

The light-emitting device according to one embodiment of the present invention can be used as indoor general lighting, indirect lighting, and vehicle lighting for use in private spaces such as living rooms and bedrooms. It can also be used as a light source for lighting equipment intended for outdoor use, such as street lights, lighting equipment installed outdoors in ports and tunnels, headlights, flashlights, and portable lanterns using LEDs.

1: Support, 2: First lead, 3: Second lead, 4: Conductive member, 10: Light-emitting element, 21, 22, 26: Wavelength conversion member, 23: Phosphor layer, 24: Bandpass filter layer, 24a: First dielectric layer, 24b: Second dielectric layer, 25: Second light-transmitting member, 30: First light-transmitting member, 32: Light-transmitting joining member, 41: Molded body, 42: Resin part, 43: Light-reflecting member, 50: Sealing member, 51: Lens part, 52: Flange part, 60: Wire, 70: Phosphor, 71: First phosphor, 72: Second phosphor, 100, 200, 300, 400: Light-emitting device, 1000: Street light, 1001: Low-position lighting device, B: Installation stand, C1, C2: Roadway, Le: Light source, P: Pole, S: Support part, T: Light-transmitting part, W: Sidewalk.

Claims (15)

A light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm;
a first phosphor having an emission peak wavelength in the range of 570 nm to 680 nm,
The light emitting device has a correlated color temperature of 1950K or less, a general color rendering index Ra of 67 or more, and a full width at half maximum of an emission spectrum showing a maximum emission intensity in an emission spectrum of the light emitting device of 110 nm or less;
A light emitting device that emits light having a melanopic ratio MR of 0.233 or less, as derived from the following formula (1):
(In formula (1), S(λ) is the spectral radiance of the light emitted by the light emitting device, V(λ) is the standard relative luminous efficiency curve for human photopic vision defined by the CIE (Commission Internationale de l'Eclairage), and R _m (λ) is the sensitivity curve of mammalian intrinsically photosensitive retinal ganglion cells (ipRGC) defined by the CIE (Commission Internationale de l'Eclairage).) A light emitting element having an emission peak wavelength in the range of 400 nm to 490 nm;
a first phosphor having an emission peak wavelength in the range of 570 nm to 680 nm,
The first phosphor includes a first nitride phosphor having a composition represented by the following formula (1A):
The light emitting device has a correlated color temperature of 1950K or less, an average color rendering index Ra of 5 to 30, and a full width at half maximum of an emission spectrum showing a maximum emission intensity in an emission spectrum of the light emitting device of 110 nm or less;
A light emitting device that emits light having a melanopic ratio MR of 0.233 or less, as derived from the following formula (1):
^M12Si5N8 _{: Eu} ( _1A )
(In formula ( 1A ), ^M1 is an alkaline earth metal element including at least one selected from the group consisting of Ca, Sr, and Ba.)
(In formula (1), S(λ) is the spectral radiance of the light emitted by the light emitting device, V(λ) is the standard relative luminous efficiency curve for human photopic vision defined by the CIE (Commission Internationale de l'Eclairage), and R _m (λ) is the sensitivity curve of mammalian intrinsically photosensitive retinal ganglion cells (ipRGC) defined by the CIE (Commission Internationale de l'Eclairage).) The light emitting device according to claim 1, wherein the first phosphor comprises at least one selected from the group consisting of a first nitride phosphor having a composition represented by the following formula (1A), a second nitride phosphor having a composition represented by the following formula (1B), a first fluoride phosphor having a composition represented by the following formula (1C), and a second fluoride phosphor having a composition represented by the following formula (1C') which has a different composition from that of formula (1C).
^M12Si5N8 _{: Eu} ( _1A )
(In formula (1A), ^M1 is an alkaline earth metal element including at least one selected from the group consisting of Ca, Sr, and Ba.)
_{SrqCasAltSiuNv : Eu} ( _{1B )}
(In formula (1B), q, s, t, u, and v respectively satisfy 0≦q<1, 0<s≦1, q+s≦1, 0.9≦t≦1.1, 0.9≦u≦1.1, and 2.5≦v≦3.5.)
A _c [M ² _1-b Mn ⁴⁺ _b F _d ] (1C)
(In formula (1C), A includes at least one selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ ; M ² includes at least one element selected from the group consisting of Group 4 elements and Group 14 elements; b satisfies 0<b<0.2; c is the absolute value of the charge of the [M ² _1-b Mn ⁴⁺ _b F _d ] ion; and d satisfies 5<d<7.)
A'_c' [M ² '_1-b' Mn ^{4 +} _b' F _d' ] (1C')
(In formula (1C'), A' includes at least one selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ ; M ² ' includes at least one element selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements; b' satisfies 0<b'<0.2;c' is the absolute value of the charge of the [M ^{2 '} _1-b' Mn ⁴⁺ _b' F _d' ] ion, and d' satisfies 5<d'<7.) The light emitting device according to claim 1 or 2, wherein the first phosphor further comprises at least one selected from the group consisting of a second nitride phosphor having a composition represented by the following formula (1B), a first fluoride phosphor having a composition represented by the following formula (1C), and a second fluoride phosphor having a composition represented by the following formula (1C') which has a different composition from that of the following formula (1C).
_{SrqCasAltSiuNv : Eu} ( _{1B )}
(In formula (1B), q, s, t, u, and v respectively satisfy 0≦q<1, 0<s≦1, q+s≦1, 0.9≦t≦1.1, 0.9≦u≦1.1, and 2.5≦v≦3.5.)
A _c [M ² _1-b Mn ⁴⁺ _b F _d ] (1C)
(In formula (1C), A includes at least one selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , M ² includes at least one element selected from the group consisting of Group 4 elements and Group 14 elements, b satisfies 0<b<0.2, c is the absolute value of the charge of the [M ² _1-b Mn ⁴⁺ _b F _d ] ion, and d satisfies 5<d<7.)
A'_c' [M ² '_1-b' Mn ^{4 +} _b' F _d' ] (1C')
(In formula (1C'), A' includes at least one selected from the group consisting of K ⁺ , Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ ; M ² ' includes at least one element selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements; b' satisfies 0<b'<0.2;c' is the absolute value of the charge of the [M ^{2 '} _1-b' Mn ⁴⁺ _b' F _d' ] ion, and d' satisfies 5<d'<7.) The light emitting device according to any one of claims 1 to 4, wherein the full width at half maximum of the emission spectrum showing the maximum emission intensity in the emission spectrum of the first phosphor is in the range of 3 nm to 120 nm. The light emitting device according to any one of claims 1 to 5, further comprising a second phosphor having an emission peak wavelength in the range of 480 nm or more and less than 570 nm. The light emitting device according to claim 6 , wherein the second phosphor comprises at least one rare earth aluminate phosphor having a composition represented by the following formula (2A):
^Ln13 ( _{Al1 -aGaa ) 5O12 :} Ce(2A)
(In formula (2A), Ln ¹ is at least one element selected from the group consisting of Y, Gd, Tb, and Lu, and a satisfies 0≦a≦0.5.) The light emitting device according to claim 6 or 7, wherein the full width at half maximum of the emission spectrum showing the maximum emission intensity in the emission spectrum of the second phosphor is in the range of 20 nm to 125 nm. The light emitting device according to any one of claims 6 to 8, wherein the content of the first phosphor relative to the total amount of the first phosphor and the second phosphor is in the range of 5% by mass to 95% by mass. The light emitting device according to any one of claims 1 to 9, which emits light with a color deviation Duv from the blackbody radiation locus of -0.008 or more and +0.008 or less. The light emitting device according to any one of claims 1 to 10, which emits light in which the second radiance in the range of 650 nm to 750 nm is 50% or less relative to the first radiance in the range of 400 nm to 750 nm, which is 100%. a wavelength conversion member including a phosphor layer including the first phosphor and a bandpass filter layer disposed on the light emission side of the phosphor layer, the wavelength conversion member being disposed on the light emission side of the light emitting element;
12. The light emitting device according to claim 1, wherein the bandpass filter layer has an average reflectance of 80% or more for light in a wavelength range of 380 nm or more and less than 495 nm, and an average reflectance of 20% or less for light in a wavelength range of more than 580 nm and less than 780 nm, for light having an incident angle in a range of 0 degrees or more and 30 degrees or less. 13. The light-emitting device according to claim 1, wherein a relative melanopic ratio MR/MR ₀ , which is a ratio of the melanopic ratio MR derived from the formula (1) of a light-emitting device emitting light having a correlated color temperature of 1950 K or less to a reference melanopic ratio MR ₀ derived from the following formula (4) of a light-emitting device emitting light having a correlated color temperature of more than 1950 K, is within a range of 10% to 99%.
(In formula (4), MR ₀ is the melanopic ratio of a light-emitting device having a correlated color temperature of more than 1950 K, S ₀ (λ) is the spectral radiance of light emitted from a light-emitting device having a correlated color temperature of more than 1950 K, V(λ) is the standard luminous efficiency curve for human photopic vision defined by the CIE (Commission Internationale de l'Eclairage), and R _m (λ) is the sensitivity curve of mammalian intrinsically photosensitive retinal ganglion cells (ipRGCs) defined by the CIE (Commission Internationale de l'Eclairage).) A lamp comprising the light emitting device according to any one of claims 1 to 13 . A lighting fixture comprising the light-emitting device according to claim 1 .